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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: amir01 on February 05, 2009, 10:55:07 PM

Title: chemistry problems: find molar mass
Post by: amir01 on February 05, 2009, 10:55:07 PM

can any help with these show me how to do them
find molar mass
K2Cr2O7

CaSO4

CuI2

H20

Al2(CO3)3

Title: Re: chemistry problems
Post by: Astrokel on February 05, 2009, 10:59:27 PM

Find each of the element in the periodic table and get its A_r. Note the subscript means how many atoms of that element. Sum all of them up to get the molar mass of the compound.

For example, Mr of CO₂ = 12 + 2(16) = 44 g/mol

Title: Re: chemistry problems
Post by: amir01 on February 05, 2009, 11:16:24 PM

thnx for help but can show me how to these too

number of moles for each of the following compounds given the mass

45.9 g Ca(OH)2

356.2 g SiO2

Title: Re: chemistry problems
Post by: Astrokel on February 05, 2009, 11:31:49 PM

Have you learn stoichiometry? No formula in your note or text?